So I did get the mr4 but when I played it would shoot 1 and sometimes 2 balls and then not fully cock. I had plenty of air, checked the o rings and oiled it but it still won't work. I an using a remote line if you think that is the problem. Please help!

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its good if people dont think there are paintball snipers. that means they havent seen one yet

That's the valve set screw. If it was loose, it could cause serious marker malfunctions as well as cause your issue. However, it is most likely not the root cause in this gentleman's case since that issue is very atypical. It would be something to check out, but I think the velocity adjuster approach may be more fruitful.